Magic mushrooms are said to blow your mind, but the hallucinogenic chemical psilocybin, the active ingredient, actually reins in key parts of the brain, according to two new studies.
The memorably vivid emotional experiences reported by mushroom users may flourish because the parts of the brain suppressed by psilocybin usually keep our world view tidy and rational.
And since the brain area affected by psilocybin can also be out of whack in mental health problems such as depression, the researchers speculate that the drug may turn out to be useful in treating mental illness.
"The brain's doing a lot to keep our experiences of the world orderly and constrained," says Robin Carhart-Harris, a post-doc in neuroscience at Imperial College London, and lead author of the studies.
The studies are among the first to use brain imaging to take a peek at the brain on psilocybin.
"Depression can be described as a particularly restrictive state of mind," Carhart-Harris told Shots. "People are stuck on how terrible they are. This seems to suggest that people can have a lifting of that negative thinking under psychedelics."
One of the studies asked 10 volunteers to recall particularly happy memories, like getting married or becoming a parent, both with and without psilocybin. The people found the memories much more vivid, visual, and happy while under the influence. That study will be published in the British Journal of Psychiatry on Thursday.
In the second study, 30 volunteers lay in an MRI machine while tripping for science. The brain scans showed less activity in areas of the brain that may act as connectors, or hubs. One of those areas, the posterior cingulate cortex, is thought to figure in consciousness and ego. It's also hyperactive in people with depression.
The researchers hadn't expected to find less brain activity with psilocybin. The thought has always been that psychedelic flights of fancy are the result of an overactive brain. The results were published Monday in the Proceedings of the National Academy of Sciences.
Serious research into psychedelic drugs was pretty much shut down after the excesses of the trip-happy 1960s. Harvard famously fired Timothy Leary in 1963 for experimenting far too enthusiastically with psilocybin and other mind-altering drugs. Psilocybin remains an illegal drug in the same category as heroin and LSD, which the Justice Department says has "no legitimate medical purpose."
Still, several recent small studies have found improvements in people with depression or obsessive-compulsive disorder after taking other psychedelics. Another found less anxiety and improved mood in cancer patients who used psilocybin.
Carhart-Harris says he was inspired to experiment with psilocybin by Roland Griffiths, a neuroscientist at Johns Hopkins University in Baltimore. Last year Griffiths reported that when he tested high doses of psilocybin in 18 volunteers, 72 percent reported profoundly spiritual experiences, as well as improvements in mood and attitude that lasted more than a year.
But those trips weren't all good; 39 percent reported extreme anxiety or fear at some point in the five 8-hour sessions. People trained as monitors kept the study participants company in an effort to reduce the impact of those bad experiences.
The next step is to see if psilocybin actually does alleviate symptoms of depression. Carhart-Harris hopes to start a pilot study asking that question by the end of the year.